1. Field of the Invention
The present invention relates to a liquid treatment process and an apparatus thereof and more particularly, to a multistage process and a package apparatus thereof for removal of dissolved, colloidal, suspended, volatile, and living contaminants from liquid.
2. Description of the Prior Art
Various types of liquid treatment processes are well known in the art. In such processes, the suspended contaminants in liquid are commonly removed by a sedimentation separation procedure wherein the particles in suspension have a specific gravity greater than that of the liquid in which they are suspended. When the specific gravity of the suspended contaminants is similar to that of the liquid, then a dissolved air flotation separation procedure is more effective and is employed. Many types of prior art processes have been developed for the separation of suspended particulates from a liquid.
It has been a standard practice for engineers to construct separate liquid treatment units to remove dissolved, colloidal, suspended, volatile and living contaminants, and to construct separate aeration units for oxidation, air dissolving and distribution. For example, for soluble iron and manganese removal in a conventional liquid treatment system, an aerator or an oxidizer is required to convert a soluble form to an insoluble form by oxidation.
Both such conventional sedimentation systems and flotation systems involve the use of separate mixers, flocculators, adsorbers, and chlorinators.
Particularly, such conventional flotation systems require separate pressure vessels for dissolving air and for air bubble generation. Therefore, the capital costs and land space requirements of such conventional systems are high. Furthermore, secondary pollution caused by the disposal of scum and sludge in liquid streams is a common problem.
Such conventional liquid treatment processes and apparatuses thereof are described in the U.S. Pat. No. 3,171,804 to Rice, U.S. Pat. No. 3,307,701 to Krofta, U.S. Pat. No. 3,820,659 to Parlette, U.S. Pat. No. 4,022,696 to Krofta, U.S. Pat. No. 4,151,093 to Krofta, U.S. Pat. No. 4,157,952 to Krofta, U.S. Pat. No. 4,184,967 to Krofta, U.S. Pat. No. 4,303,5I7 to Love et al, U.S. Pat. No. 4,377,485 to Krofta, U.S. Pat. No. 4,626,345 to Krofta, U.S. Pat. No. 4,626,346 to Hall, U.S. Pat. No. 4,673,494 to Krofta, U.S. Pat. No. 4,673,498 to Swinney et al, U.S. Pat. No. 4,673,500 to Hoofnagle et al and L. K. Wang, using Air Flotation and Filtration in Color and Giardia removal. U.S. Department of Commerce, National Technical Information Service, Springfield, Va., USA. Technical Report No. PB89-158398/AS. October 1988. L. K. Wang and W. J. Mohoney. Treatment of Storm Run-off by Oil-Water Separation, Flotation, Filtration and Adsorption, Part A: Wastewater Treatment. Proceedings of the 44th Industrial Waste Conference, P. 655-666, May 1989. L.K. Wang, M.H.S. Wang and W.J. Mahoney. Treatment of Storm Run-off by Oil-Water Separation, Flotation, Filtration and Adsorption: Part B: Waste Sludge, Management. Proceedings of the 44th Industrial Waste Conference, P. 667-673, May 1989.